Human T-cell leukemia-lymphotropic virus (HTLV) refers to a family of T cell tropic retroviruses. Such viruses, which have a role in causing certain T cell neoplasms, are presently divided into three main types or subgroups: (1) HTLV-type I (HTLV-I), which appears to cause adult T-cell leukemia-lymphoma (ATLL); (2) HTLV-type II (HTLV-II), which has been isolated from an individual having a T-cell variant of hairy cell leukemia; and (3) HTLV-type III (HTLV-III), which has been identified as the etiologic agent of acquired immune deficiency syndrome (AIDS). HTLV-III is also known as lymphadenopathy-associated virus (LAV), AIDS related virus (ARV) and human immunodeficiency virus (HIV). Popovic, M. et al., Science, 224: 497-500 (1984); Gallo, R. C. et al., Science, 224: 500-503 (1984); Wong-Staal, F. and Gallo, R. C., Nature, 317: 395-403 (1985); and Curran, J. W. et al., Science, 229: 1352-1357 (1985).
AIDS was first recognized in 1981 and since that time, the disease has come to be recognized as a new epidemic. RNA Tumor Viruses (2d edition), Volume 2, pp 437-443, Cold Spring Harbor Laboratory (1985).
Patients with AIDS exhibit clinical manifestations which include severe immunodeficiency which generally involves a depletion of helper T lymphocytes; malignancies; and opportunistic infections. The disease at this time is incurable and the mortality rate among AIDS patients is high.
Because the disease has severe, generally life threatening effects, there is great interest in finding means of protecting the population from it and of treating those who contract it. At the present time, much effort is being put into developing methods of detecting the presence of HTLV-III in body tissues and fluids (e.g., blood, saliva) and into developing vaccines which will protect recipients from HTLV-III. However, there is no known method which is satisfactory either for preventing the disease or for treating those who become infected with the virus. In fact, current efforts to develop a broad spectrum anti-HTLV-III vaccine may be seriously compromised, in light of the variation in envelope proteins (which are the principal antigenic determinants of the virus) observed among various strains of HTLV-III. Hahn, G. H. et al., Proceedings of the National Academy of Sciences, USA, 82: 4813-4817 (1985); Benn, S. et al., Sciences, 230: 949-951 (1985). Other methods of blocking the effects of the virus are clearly needed.